macintosh freeware/cheapware ?

Hello all ye tuning wizards-

I am interested in creating midi files using various equal
temperaments. I have seen SCALA used in DOS but has no MAC version. Is
there other software which enables me to specify scale degrees of a
given equal-division and compile them into a file?
If you can point me to a general site where I can look for info, that
would be helpful as well, for I am new to this world. (but i was not
born yesterday.)

Thanks.